Two-cycle, air-cooled uniflow gasoline engine for powering a portable tool
US5383427A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 19, 1993 |
| Grant date | Jan 24, 1995 |
| Priority date | — |
| Expiry date | Jul 19, 2013 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02B2075/025
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A flexible line trimmer is powered by a two-stroke internal combustion engine. The engine is scavenged in a uniflow fashion and has a scavenging cylinder and an exhaust cylinder connected by a common combustion chamber. Each cylinder has a piston turning one of two cantilevered crankshafts that are geared through adjacent counterweights having integrally formed teeth. The crankshafts extend in opposite directions for self-balancing. One crankshaft is coupled to a flywheel fan and other coupled to a starter. A fuel and air mixture is transferred to a common crankcase for the crankshafts through an intake port located on the exhaust cylinder. The piston of the scavenge cylinder is retarded with respect to the exhaust cylinder. An exhaust window opens prior to a scavenge window. The scavenge window closes after the exhaust window. The exhaust window is shortened to improve crankcase compression. The cylinders are joined in a siamese fashion, fabricated from a single piece, and skewed toward each other. A carburetor and muffler are mounted on substantially opposite sides of the exhaust cylinder.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.